Yes, this karma thing is very confusing... If, as SC says, minus karma is good... then SanPer58's rating of +445/-229 is totally misleading. There's no way, in my mind, that more people are unhappy (+ karma) with his posts then are happy (- karma) with them.
Maybe Foamy could chime in here because I read somewhere on here soon after I became a member, an explanation of his about karma, but it didn't answer the + / - (good / bad) question for me.